Cities and counties in Kansas will be barred from requiring private contractors to pay union-scale wages on public projects, starting in July.

Gov. Sam Brownback signed a bill into law Tuesday to prohibit local governments from requiring private firms to pay employees more than the federal minimum wage for work on public contracts.

The legislation was aimed at local policies requiring contractors to pay so-called prevailing wages. The federal Department of Labor sets those rates, and critics say they’re often based on union scales.

Wyandotte County has a prevailing wage policy that will be repealed by the new law.

Brownback’s fellow Republicans said such a law would lower the cost of public projects. Democrats said prevailing wage policies don’t boost costs and ensure workers earn a decent living.